I'm Here! is a great utility that lets users share their location live on a Google Map with family, friends and colleagues. The site uses Fire Eagle to update users' locations.
Registered users have full control on the sharing of their location with other members. They can also choose how they wish to use the utility. For example, the site could be used to share current activity with friends and colleagues or it could be used to track a child. It could even be used to organise location based games.
Because this application uses Fire Eagle it may meet that service's request quota at times. If that occurs users cannot sign in.